I'm not sure that would help much. I think the risks and uncertainties of long-term R&D increase much faster than any tax incentive can compensate for. My favorite story is the (real) history of Silicon Valley. I once thought that was a proof for what private enterprise can accomplish. Turns out that SV is actually based on the unrestrained spending on R&D (of borrowed money, of course) by government during WWII. [0]

Private enterprise wants a level of certainty, long-term or not. Tax incentives don't reduce the uncertainty. I doubt that money is the major constraint. Look at some major corporations basically "swimming" in money, and they also should be able to borrow easily (and cheaply) at this time.

[0] https://www.youtube.com/watch?v=ZTC_RxWN_xo